1. Field Of The Invention
This invention relates to a downhole drilling apparatus which has a cyclone separator disposed therein for separating drilling mud into a more dense portion and a less dense portion, and more particularly, to an apparatus in which the cyclone separator includes an easily assembled multi-piece cartridge positionable in the central opening of a barrel, the barrel having an upper end engageable with a drill string and a lower end engageable with a drill bit.
2. Description Of The Prior Art
Separator subs of the general type disclosed in the present invention are known in the art. In particular, U.S. Pat. No. 4,475,603 to Hayatdavoudi and U.S. Pat. No. 4,488,607 to Hayatdavoudi and Adams are pertinent. Both of these references disclose a separator sub requiring complex assembly. An upper adapter, a lower adapter and an outer housing are heated to cause them to expand. An unheated cyclone housing formed by several segments which fit together in a tongue-in-groove fashion requiring an adhesive sealant therebetween are placed in the outer housing between the upper and lower adapters. The outer housing is then welded to the upper and lower adapters and cooled. Once cooled, the heated parts shrink so that the segments of the cyclone housing are held together by axial compression. The liquid adhesive sealant prevents leakage between the stacked segments.
The problem with such construction is there are a large number of individually machined, mating segments in the cyclone housing, requiring a sealant therebetween, and the heating operation during assembly is difficult and expensive. Further, the result is an integrally welded unit which cannot be disassembled easily for replacement of parts. The apparatus of the present invention solves these problems by having a cyclone separator assembly which is positionable in a barrel having an upper end attached to the drill string and a lower end attached to the drill bit. The cyclone separator assembly is easily removed from the barrel and disassembled into its various components for repair and replacement of worn parts. Further, components of different sizes appropriate for various drilling conditions may be used.